Towards atomic resolution in sodium titanate nanotubes using near-edge X-ray-absorption fine-structure spectromicroscopy combined with multichannel multiple-scattering calculations

• Carla Bittencourt,
• Peter Krüger,
• Maureen J. Lagos,
• Xiaoxing Ke,
• Gustaaf Van Tendeloo,
• Chris Ewels,
• Polona Umek and
• Peter Guttmann

Beilstein J. Nanotechnol. 2012, 3, 789–797, doi:10.3762/bjnano.3.88

• -hydroxyl O atoms, the A/B intensity ratio is found to be simply correlated with the O–Ti coordination: A > B for the 2-fold sites O4, O6; A ≈ B for the 3-fold site O8; and A < B for the 4-fold sites O9, O10. Thus, the A/B intensity ratio at the O K-edge XAS provides a direct local measure of the

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• -modulation infrared reflection absorption spectroscopy (PM-IRAS) [15][16][17] or X-ray absorption spectroscopy (XAS) techniques [18][19], which allow us to gain detailed information on the structure, elemental/molecular chemical composition and electronic/vibrational properties of the catalyst surface and

Nanoscaled alloy formation from self-assembled elemental Co nanoparticles on top of Pt films

• Luyang Han,
• Ulf Wiedwald,
• Johannes Biskupek,
• Kai Fauth,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2011, 2, 473–485, doi:10.3762/bjnano.2.51

• XAS energy scans, obtained in applied fields of µ0H = ± 1 T, sufficient to achieve magnetic saturation. While the Co L3,2 resonances as well as the magnetic dichroism are clearly visible, we note that even the resonant Co signal amounts to only a fraction (≈1%) of the strong TEY background (≈170 pA

Simple theoretical analysis of the photoemission from quantum confined effective mass superlattices of optoelectronic materials

• Debashis De,
• Sitangshu Bhattacharya,
• S. M. Adhikari,
• A. Kumar,
• P. K. Bose and
• K. P. Ghatak

Beilstein J. Nanotechnol. 2011, 2, 339–362, doi:10.3762/bjnano.2.40

• superlattices, together with quantum well superlattices under magnetic quantization, has also been investigated in this regard. It appears, taking HgTe/Hg1−xCdxTe and InxGa1−xAs/InP effective mass superlattices, that the photoemission from these quantized structures is enhanced with increasing photon energy in

• ], etc. Among the III–V SLs, the GaAs/Ga1−xAlxAs SL has been extensively investigated, in which the GaAs layers form the quantum wells and Ga1−xAl1−xAs layers form the potential barriers. The III–V SLs are being extensively used in the realization of high speed optoelectronic devices [10]. The II–VI [11

• figure have been drawn for the perturbed two band model of Kane and that of perturbed parabolic energy bands respectively. The curves (d), (e) and (f) in the same figure exhibit the corresponding plots of QW InxGa1−xAs/InP effective mass SL. Figure 2 to Figure 5 show the variations of the normalized

Extended X-ray absorption fine structure of bimetallic nanoparticles

• Carolin Antoniak

Beilstein J. Nanotechnol. 2011, 2, 237–251, doi:10.3762/bjnano.2.28

• density functional theory calculations on the magnetic properties. Keywords: bimetallic alloys; EXAFS; FePt; nanoparticles; wavelets; XAS; Introduction Since the discovery of X-rays in 1895 by Röntgen, the field of spectroscopy methods using this regime of the electromagnetic spectrum has reached a very

• on state-of-the-art X-ray absorption spectroscopy (XAS) on 3rd generation synchrotron sources such as the ESRF and BESSY II. In general, XAS deals with the excitation of core-level electrons, with their element-specific binding energies, by incident X-rays. After absorption of an X-ray photon, a core

• comparing the intensity of incident X-rays to the intensity of X-rays passed through the sample. At low photoelectron energies, ranging from the absorption edge up to about 100 eV above, XAS is sensitive to the electronic structure around the absorbing atom and gives rise to the X-ray absorption near-edge

Zirconium nanoparticles prepared by the reduction of zirconium oxide using the RAPET method

• Michal Eshed,
• Swati Pol,
• Aharon Gedanken and
• Mahalingam Balasubramanian

Beilstein J. Nanotechnol. 2011, 2, 198–203, doi:10.3762/bjnano.2.23

• between 20° and 24° in Figure 1b, is due to the mylar layer that covers the sample in the specially inert XRD cell [12] designed to avoid the oxidation of the Zr sample. However, further proof for the successful fabrication of metallic zirconium is required. X-ray absorption spectroscopy (XAS) was

• employed to confirm the formation of metallic Zr synthesized (Zr-syn) by RAPET of ZrO2. The techniques of XAS, namely X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), are used to probe local structural details [13] around specific metal atoms and to discern

• the oxidation states of the metal, here the zirconium atom. The Zr K-edge XAS of Zr-syn is compared with the standards, ZrO2 (also used as a starting material) and metallic hexagonal close packed (hcp) Zr as shown in Figure 2. The normalized XANES spectrum (Figure 2a) shows a comparison of the

Structure, morphology, and magnetic properties of Fe nanoparticles deposited onto single-crystalline surfaces

• Armin Kleibert,
• Wolfgang Rosellen,
• Mathias Getzlaff and
• Joachim Bansmann

Beilstein J. Nanotechnol. 2011, 2, 47–56, doi:10.3762/bjnano.2.6

• of the equilibrium shape of pure crystalline Fe particles as expected from a Wulff construction in the present particle size range [32]. (a) X-ray absorption spectra of the Ni(111) substrate. Inset: Schematics of the experiment. (b) XAS spectra of the Fe NPs with a diameter of (7.6 ± 1.5) nm. (c),(d

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• formation on the corresponding magnetic properties are by no means clear-cut [64], one nevertheless has to take this into consideration. Indeed, close inspection of in situ X-ray absorption spectra (XAS) on Co NPs immediately after reduction in a hydrogen plasma revealed a significant shoulder 2 eV above

• the Co-L3,2 absorption maxima caused by hydrogen uptake. In this particular case, however, the hydrogen could be expelled by annealing at 650 °C for 5 min [65], and led to complete disappearance of the above XAS shoulder. However, there is no general rule on this issue and hydrogen uptake during the